Urinary management is of critical need in the acute and long term care settings. Urinary issues are generally grouped into two primary categories: failure to drain; and failure to contain. In the case of failure to drain, the patient cannot spontaneously drain urine from the bladder. The general solution to this problem is to catheterize the patient. In the case of failure to contain, the patient cannot contain the urine within their body until a convenient and expedient time. When patients are not conscious or cognizant, they are typically catheterized. Patients who are aware but non-ambulatory often utilize a manual collector for assistance, such as a bedpan, a male urinal, or an adult diaper. These can be cumbersome to use, and sometimes result in spills on or around the patient. Also, such manual collectors may require frequent changes, placing additional burden on caregivers. When it is desired to monitor the urine output, very often medical staff catheterize a patient even when catheterization is not otherwise required. Catheterization provides a means by which urine can be monitored more easily than with a manual collector.
There is a growing problem with nosocomial infections and a high incidence of catheter-related urinary tract infections (UTIs). Catheter associated UTI is the most common nosocomial infection in hospitals and nursing homes, accounting for up to 40% of all institutionally acquired infections, or more than 1 million infections in U.S. hospitals each year. There is considerable pressure on the healthcare and nursing profession to reduce such infection.
U.S. Pat. Nos. 5,002,541, 4,747,166 and 4,631,061 describe human urine aspiration systems. The urine aspiration systems include an electric pump for applying suction to a urinal. The urinal includes a liquid sensor for automatically activating the pump when the presence of liquid urine is detected. The three patents all describe liquid-contact sensors in the form of electrodes forming a normally open circuit that is closed by electrical conduction through liquid, when the sensor is contacted by liquid. However, there are obvious concerns about the possibility of electrical current leaking from the electrodes, through the conductive urine, to the skin. Moreover, the sensor is necessarily used in close proximity to the sensitive genital area, increasing the concerns of leakage of current that is applied by the electrodes.
The last mentioned patent, U.S. Pat. No. 4,631,061, also suggests the possibility of using at least one pair of optical elements, formed by opposed optical fibers integrated into the liquid passage of the urinal or collection tube to sense the liquid. This is said to avoid electrical currents applied to the urinal. However, the design is very expensive and impractical commercially. It requires at least one pair of optical elements that are optically aligned in a pad with a beam of light passing between the pair of optical elements to sense the presence of liquid. It also needs an optically transparent window to allow the beam of light to pass through. Any residues or moisture condensation could easily cloud the window and falsely trigger the pump to turn on. The optical fibers are expensive items, and integrating these into the urinal or tubing increases the cost of the urinal or tubing, which are preferably disposable for hygiene reasons. Moreover, the electro-optic part is remote from the urinal, and has to be connected by delicate and expensive optical fibers, making the system delicate and expensive as a whole.
A further issue is a design of a body interface device that is comfortable and discrete to wear, yet also provides secure protection against leakage of discharged urine, and allows rapid sensing of urine discharge. The difficulty is especially apparent in devices for female wearers. Achieving a reliable seal around the female genital area is difficult, especially in a device that is conformable so as to be comfortable. Moreover, if a urine discharge is not sensed quickly and reliably, urine may leak as a result of overspillage. This problem is exacerbated if the device is intended to be compact, as there is then little volume in the body interface device to accommodate initial urine discharge.
It would be desirable to improve on prior art designs of aspirated liquid removal systems, especially in terms of urine detection and body interface devices, in order to satisfy commercial need and improve customer acceptance.